Proclaiming July 10 as "710 Day" in the city, Alhambra reaffirmed its support for a controversial tunnel that would connect the Long Beach and Foothill freeways.

“We as a city want to raise awareness that now is the time [the 710 freeway] can be completed,” Alhambra Mayor Steve Placido said at a news conference Tuesday at City Hall.

Extending the 710 Freeway from its terminus in Alhambra via a tunnel to the 210 Freeway in Pasadena has long been a controversial proposal, with a collage of politically powerful neighborhoods and elected officials all coming down hard on the idea.

Opponents argue the connection would bring a deluge of big-rig traffic and corresponding noise and air pollution.

Officials in Glendale, Pasadena, South Pasadena, Sierra Madre, La Cañada Flintridge and Los Angeles have all issued public statements opposing the 710 Freeway extension, as well as state and federal representatives.

Combined with an active coalition of residents opposed to the proposal — the No 710 Action Committee — the public argument in favor of a tunnel has hardly registered.

The Los Angeles Country Metropolitan Transportation Authority is currently conducting an environmental study of five options for reducing congestion in the 710 gap, which in addition to the tunnel, include light rail and bus transit. A first draft of the study is expected to be completed in 2014.

Alhambra has long supported extending the 710 Freeway from its terminus, where vehicles currently spill out onto city streets in an effort to follow myriad urban paths to other freeways.

Placido said the city was stepping forward now because the financial commitment was there for a full environmental study of the options through Measure R — the half-cent sales tax for transportation projects approved by county voters in 2008. The review also has the backing of the MTA and the California Department of Transportation.